In the manufacture of such modules it is customary to provide a conductive lead frame which is subsequently split into a multiplicity of sections each forming a chip-supporting plate along with an associated set of tongues, at least one tongue being rigid with the plate and being initially connected with the remaining tongues by severable bridges. The number of tongues on each lead-frame section is limited by mechanical as well as electrical considerations; where a large number of such tongues is required, two symmetrical tongue arrays may be provided on opposite sides of the block in a so-called dual-in-line arrangement (see, for example, commonly owned U.S. Pat. No. 3,689,683).
Thus, a standardized lead frame particularly designed for use with low-voltage power transistors comprises three tongues per section, i.e. a central tongue integral with the plate and two flanking tongues detachable therefrom; such a lead frame is commercially available under the designation TO-220 and operates with a temperature rise of about 3.degree. C. per watt.